<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="./vue.js"></script>
</head>
<body>
<div id="root">
  <button @click="num++">{{num}}</button>
  <input v-model.num="num" type="text">
</div>
</body>
<script>
  var vm = new Vue({
    el: '#root',
    data: {
      num: 0,
    }
  })
</script>
</html>